The present invention relates generally to fuel filler door latch systems for motor vehicles and, more particularly, to incorporation of a biasing mechanism for moving the fuel filler door to an open position upon release of the latch system.
In an effort to inhibit unauthorized access to a vehicle's fuel tank, some motor vehicles are now equipped with fuel filler door latch systems. Conventional latch systems include a striker bar fixed to the fuel filler door and a latch member mounted to the vehicle body. When the fuel filler door is closed, the latch member is in a "latched" position for lockingly engaging the striker bar. To open the fuel filler door and permit access to the fuel filler cap, the latch member is selectively moved to an "unlatched" position for releasing the striker bar. In key-actuated latch systems, the latch member is moved from its latched position to its unlatched position upon insertion and rotation of the key in a conventional lock mounted to the fuel filler door.
As a convenience option, some motor vehicles are now equipped with fuel filler door latch systems having a remotely-actuated release mechanism. A remotely-actuated release mechanism permits a vehicle occupant seated within the passenger compartment to release the fuel filler door prior to exiting the vehicle. Some remotely-actuated release mechanisms use a linear actuation cable or linkage for manually moving the latch member to its unlatched position in response to the vehicle occupant pulling a spring-biased release handle located within the passenger compartment. Alternatively, some vehicles are equipped with fuel filler door latch systems having an electrically-controlled release mechanism. Such electrically-controlled release mechanisms typically include an electromagnetic solenoid assembly, a push-button release switch located in the passenger compartment of the automobile, and an electrical connection between the solenoid assembly and the release button. When the vehicle occupant depresses the push-button release switch, the solenoid assembly is energized for causing a spring-biased armature associated with the solenoid assembly to move. Since the latch member is mounted for concurrent movement with the armature, such movement of the armature results in corresponding movement of the latch member to its unlatched position, thereby releasing the fuel filler door. These remotely-actuated latch systems provide both a measure of security in limiting access to the automobile's fuel tank and a measure of convenience by allowing a person to remotely open the fuel filler door from within the automobile passenger compartment.
To facilitate movement of the fuel filler door to a partially open position, the above-noted latch systems also typically include a biasing mechanism for forcibly urging the fuel filler door to move away from the automobile body once the striker bar has been released. Typically, such a biasing mechanism includes either a door-mounted spring or a hinge-mounted spring. A door-mounted spring is mounted directly to the distal end of the fuel filler door such that when the fuel filler door is closed, the spring is compressed and bears against a surface in a recessed well portion of the automobile body. When the release mechanism is actuated and the fuel filler door is released, the compressive force acting on the door-mounted spring urges the fuel filler door to move outwardly from its closed position to its open position. Alternatively, a hinge-mounted spring can be mounted within the fuel filler door cavity between the gooseneck hinge of the fuel filler door and an inner wall of the automobile body. Such a hinge-mounted spring is compressed between the body wall and the hinge when the fuel filler door is closed. When the release mechanism is actuated and the door is released, the hinge-mounted spring urges the fuel filler door to move away from the automobile body by applying the compressive load on the gooseneck hinge.
Although both above-noted types of conventional biasing mechanisms perform satisfactorily for their intended purpose of opening the fuel filler door, both have associated limitations. For instance, the door-mounted spring tends to create wear on the painted well surface of the automobile body due to its contact therewith when the door is closed and when the spring urges the door away from the automobile body upon the actuation of the release mechanism. Such wear may permit subsequent corrosion and deterioration of the automobile body in the fuel filler door area. Also, the door-mounted spring is aesthetically undesirable and susceptible to damage since it is external to the fuel filler chamber so as to be visible when the fuel filler door is open. With respect to hinge-mounted springs, such a spring is typically designed with a relatively large spring constant since it must be compact to fit in the limited space between the fuel filler door wall and the hinge. As such, the hinge-mounted spring exerts a large load against the gooseneck hinge which can cause the fuel filler door to open too far. Further, the fuel filler door assembly is typically installed in the vehicle before it is painted. Thus, the hinge-mounted spring is often exposed to elevated temperatures in the paint curing ovens which can cause detrimental stress relief, thereby decreasing the spring constant and the ability of the spring to exert the desired load on the hinge. Also, hinge-mounted springs can be subjected to over-stressing during assembly.